More than 10 South Sudanese have been captured in the North Kordofan State in central Sudan, sources say.

The Sudanese military has captured South Sudanese fighting alongside the Rapid Support Forces (RSF) paramilitary group in battles that broke out in a central region of the country this week, according to sources in the government-aligned Sudanese Armed Forces (SAF).

The sources told Al Jazeera that the army and its allied forces captured more than 10 members on Thursday in the towns of Kazqil and al-Rayash in the North Kordofan State in central Sudan.

They also said that Sudan is about to address the government of South Sudan and provide official evidence proving the participation of these elements in the ranks of the RSF.

In a separate development, Hamid Ali Abubakar, security adviser to RSF commander Mohamed Hamdan Dagalo, was killed along with several aides in a drone attack carried out by SAF near the city of Zalingei, the capital of Central Darfur state, RSF security adviser al-Basha Tabiq said on Thursday evening.

Tabiq announced the death in a post on Facebook, mourning “Commander Adviser Hamid Ali Abubakar”, who also led the RSF’s “al-Saif al-Battar” military unit, which operates mainly in northern, central and western parts of the Darfur region.

Tabiq accused the SAF of “assassinating” Abubakar and warned it would “pay a heavy price for this crime”.

The three Kordofan states – North, West, and South – have seen weeks of fierce fighting between the army and the RSF, prompting tens of thousands of people to flee.

Worsening humanitarian crisis

Thousands of families fleeing renewed fighting in Kordofan and Darfur have arrived in the city of Kosti, only to find overcrowded camps and dwindling international support.

Meanwhile, the North Darfur Emergency Chambers Council warned of the worsening humanitarian disaster in the Umbro locality of North Darfur State, where heavy clashes are ongoing amid an RSF offensive.

The council said the region is experiencing tragic conditions that have led to the forced displacement of more than 6,500 families.

Of Sudan’s 18 states, the RSF controls all five states of the Darfur region in the west, except for some northern parts of North Darfur that remain under army control.

The army, meanwhile, holds most areas of the remaining 13 states in the south, north, east, and centre, including the capital Khartoum.

Sudan’s humanitarian crisis has sharply worsened since the war between the army and the RSF erupted in April 2023 over a dispute on unifying the military establishment, killing tens of thousands and displacing millions.